1. Field of the Invention
This invention relates to towing apparatus, and, more particularly, to novel systems and methods for securing trailers to towing vehicles with hitches.
2. State of the Art
Trailers have been towed since the earliest days of the wheel. A cart or wagon towed behind an animal is a trailer. In modem times, trailers are secured to towing vehicles by a multiplicity of methods, including frame-mounted hitches and bumper-mounted hitches. Tractor-trailer rigs use fifth-wheel towing systems. Similarly, recreational vehicles sometimes use fifth-wheel towing systems or often a receiver-type mounted ball hitch.
A receiver hitch relies on a receiver cavity or tube securely mounted to the frame of a towing vehicle. The receiver is reinforced and provided with an aperture for receiving a trunnion. A trunnion may be secured into the receiver. On the trunnion may be mounted a hitch. The hitch may be a pin hitch or ball hitch, typically, but need not be limited thereto.
For recreational users, receiver-type hitches present several common problems. The more important problem may be the difficulty of attaching a greasy hitch to a vehicle and disattaching the same after use. Although receiver-type hitches are generally adaptable to receive various trunnions with various types of hitches, the very nature of a receiver hitch may make it problematic. If a trunnion is not removed after use, then a person may accidentally strike a shin or knee on the extending hitch or trunnion when no towed vehicle is attached. If the hitch is removed, it is cumbersome to move, requires some immediate storage place, and may be filthy with grease. Due to the weight of the hitch and trunnion assembly, a person removing the trunnion and hitch from a receiver is likely to soil clothing.
Another problem with many types of hitches is the adjustment of altitude of the hitch itself. Recreational users may have multiple towed vehicles. For example, a boat trailer, a snowmobile trailer, a utility hauling trailer, and the like may be manufactured at different and arbitrary hitch heights. Similarly, a hitch may be used on different vehicles having different heights. Accordingly, it may be advantageous to provide a hitch mount that may be mounted on any convenient mount, yet be easily adjustable, storable, secure, and so forth.
Thus, it would be an advance in the art to provide a hitch mount that can be stowed without projecting inconveniently far from the bumper, substantially within the envelope of a vehicle, or even without extending behind the bumper on certain embodiments. Ready access, and substantially weightless or self-supporting deployment of a hitch is extremely desirable as are adjustable height, stowaway positioning, and continual connection.
Along with an adjustment in altitude, it is common to use different sizes of ball hitches. Accordingly, selective stowage and presentation, selectivity of multiple sizes of ball hitches on a single mount, without having to use a wrench to replace the ball hitch, alone or in combination would be a benefit and convenience.
A ball hitch may be formed to have an integral stud acting as a bolt for securing the ball to a mounting location. A lightweight ball hitch may be hollow to receive a bolt therethrough from the top, in an axial direction. However, any penetration into a ball hitch will necessarily affect the strength of the penetrated member. Moreover, a ball hitch must have a neck of substantially smaller diameter than that of the ball itself. The difference in diameters permits the capturing element on a trailer tongue to secure the ball therein, while still being able to rotate in all necessary degrees of freedom while under way.
Meanwhile, a ball hitch has a load rating associated with the overall strength of the ball hitch, including the ball, the neck, and the stud securing the ball hitch to a mount on a vehicle. The strength of the neck or the stud may limit the load rating of a ball hitch. Thus, the neck must be smaller than the ball, yet cannot be too small. Similarly, the stud must be sufficiently large in diameter to provide sufficient strength.
If a conventional ball hitch were to be drilled to receive a stud or bolt of a size corresponding to the stud of a conventional hitch of that same size, the neck would be so weakened as to render the ball hitch unfit for service. In attempting to maintain strength, a balance simply does not exist for balancing a load rating of a ball, a neck, and a bolt penetrating into the neck. Only by welding a ball onto a mounting surface has one been able to provide multiple ball hitches on a mount otherwise lacking space or other geometric considerations necessary to accommodate the two corresponding studs.
Thus it would be an advance in the art to provide a set of ball hitches having sufficient design freedom to effectively always have a balance of strength capacity in the ball, neck (shank), flange, and stud of one hitch to support it properly at the load rating typical of a ball hitch of corresponding diameter. It would be a substantial improvement also to provide another ball hitch, in such a set, having a penetration, threads, pedestal (extended shank, axially extended flange), neck, and ball configured to mount opposite and matingly engaged with the stud of the first ball.
One may desire that the sizes and ratings of two ball hitches to be used together be different, yet that each ball hitch be adequately supported, with the support of loading in all portions or regions thereof (neck, ball, stud, etc.) reasonably balanced. Accordingly, it would be an advance in the art to provide a method for designing a ball hitch, or a set of ball hitches that could accommodate the load and geometric considerations that both balls will need to function at full, rated load, and all expected conditions.